clang/lib/Frontend/FrontendAction.cpp - toolchain/llvm-project - Gitiles

 //===--- FrontendAction.cpp -----------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//

 #include "clang/Frontend/FrontendAction.h"
 #include "clang/AST/ASTConsumer.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/DeclGroup.h"
 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Frontend/ASTUnit.h"
 #include "clang/Frontend/ChainedIncludesSource.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/FrontendDiagnostic.h"
 #include "clang/Frontend/FrontendPluginRegistry.h"
 #include "clang/Frontend/MultiplexConsumer.h"
 #include "clang/Parse/ParseAST.h"
 #include "clang/Serialization/ASTDeserializationListener.h"
 #include "clang/Serialization/ASTReader.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace clang;

 namespace {

 class DelegatingDeserializationListener : public ASTDeserializationListener {
   ASTDeserializationListener *Previous;

 public:
   explicit DelegatingDeserializationListener(
                                            ASTDeserializationListener *Previous)
     : Previous(Previous) { }

   virtual void ReaderInitialized(ASTReader *Reader) {
     if (Previous)
       Previous->ReaderInitialized(Reader);
   }
   virtual void IdentifierRead(serialization::IdentID ID,
                               IdentifierInfo *II) {
     if (Previous)
       Previous->IdentifierRead(ID, II);
   }
   virtual void TypeRead(serialization::TypeIdx Idx, QualType T) {
     if (Previous)
       Previous->TypeRead(Idx, T);
   }
   virtual void DeclRead(serialization::DeclID ID, const Decl *D) {
     if (Previous)
       Previous->DeclRead(ID, D);
   }
   virtual void SelectorRead(serialization::SelectorID ID, Selector Sel) {
     if (Previous)
       Previous->SelectorRead(ID, Sel);
   }
   virtual void MacroDefinitionRead(serialization::PreprocessedEntityID PPID,
                                    MacroDefinition *MD) {
     if (Previous)
       Previous->MacroDefinitionRead(PPID, MD);
   }
 };

 /// \brief Dumps deserialized declarations.
 class DeserializedDeclsDumper : public DelegatingDeserializationListener {
 public:
   explicit DeserializedDeclsDumper(ASTDeserializationListener *Previous)
     : DelegatingDeserializationListener(Previous) { }

   virtual void DeclRead(serialization::DeclID ID, const Decl *D) {
     llvm::outs() << "PCH DECL: " << D->getDeclKindName();
     if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
       llvm::outs() << " - " << ND->getNameAsString();
     llvm::outs() << "\n";

     DelegatingDeserializationListener::DeclRead(ID, D);
   }
 };

   /// \brief Checks deserialized declarations and emits error if a name
   /// matches one given in command-line using -error-on-deserialized-decl.
   class DeserializedDeclsChecker : public DelegatingDeserializationListener {
     ASTContext &Ctx;
     std::set<std::string> NamesToCheck;

   public:
     DeserializedDeclsChecker(ASTContext &Ctx,
                              const std::set<std::string> &NamesToCheck,
                              ASTDeserializationListener *Previous)
       : DelegatingDeserializationListener(Previous),
         Ctx(Ctx), NamesToCheck(NamesToCheck) { }

     virtual void DeclRead(serialization::DeclID ID, const Decl *D) {
       if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
         if (NamesToCheck.find(ND->getNameAsString()) != NamesToCheck.end()) {
           unsigned DiagID
             = Ctx.getDiagnostics().getCustomDiagID(DiagnosticsEngine::Error,
                                                    "%0 was deserialized");
           Ctx.getDiagnostics().Report(Ctx.getFullLoc(D->getLocation()), DiagID)
               << ND->getNameAsString();
         }

       DelegatingDeserializationListener::DeclRead(ID, D);
     }
 };

 } // end anonymous namespace

 FrontendAction::FrontendAction() : Instance(0) {}

 FrontendAction::~FrontendAction() {}

 void FrontendAction::setCurrentFile(StringRef Value, InputKind Kind,
                                     ASTUnit *AST) {
   CurrentFile = Value;
   CurrentFileKind = Kind;
   CurrentASTUnit.reset(AST);
 }

 ASTConsumer* FrontendAction::CreateWrappedASTConsumer(CompilerInstance &CI,
                                                       StringRef InFile) {
   ASTConsumer* Consumer = CreateASTConsumer(CI, InFile);
   if (!Consumer)
     return 0;

   if (CI.getFrontendOpts().AddPluginActions.size() == 0)
     return Consumer;

   // Make sure the non-plugin consumer is first, so that plugins can't
   // modifiy the AST.
   std::vector<ASTConsumer*> Consumers(1, Consumer);

   for (size_t i = 0, e = CI.getFrontendOpts().AddPluginActions.size();
        i != e; ++i) {
     // This is O(|plugins| * |add_plugins|), but since both numbers are
     // way below 50 in practice, that's ok.
     for (FrontendPluginRegistry::iterator
         it = FrontendPluginRegistry::begin(),
         ie = FrontendPluginRegistry::end();
         it != ie; ++it) {
       if (it->getName() == CI.getFrontendOpts().AddPluginActions[i]) {
         llvm::OwningPtr<PluginASTAction> P(it->instantiate());
         FrontendAction* c = P.get();
         if (P->ParseArgs(CI, CI.getFrontendOpts().AddPluginArgs[i]))
           Consumers.push_back(c->CreateASTConsumer(CI, InFile));
       }
     }
   }

   return new MultiplexConsumer(Consumers);
 }

 bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
                                      StringRef Filename,
                                      InputKind InputKind) {
   assert(!Instance && "Already processing a source file!");
   assert(!Filename.empty() && "Unexpected empty filename!");
   setCurrentFile(Filename, InputKind);
   setCompilerInstance(&CI);

   if (!BeginInvocation(CI))
     goto failure;

   // AST files follow a very different path, since they share objects via the
   // AST unit.
   if (InputKind == IK_AST) {
     assert(!usesPreprocessorOnly() &&
            "Attempt to pass AST file to preprocessor only action!");
     assert(hasASTFileSupport() &&
            "This action does not have AST file support!");

     llvm::IntrusiveRefCntPtr<DiagnosticsEngine> Diags(&CI.getDiagnostics());
     std::string Error;
     ASTUnit *AST = ASTUnit::LoadFromASTFile(Filename, Diags,
                                             CI.getFileSystemOpts());
     if (!AST)
       goto failure;

     setCurrentFile(Filename, InputKind, AST);

     // Set the shared objects, these are reset when we finish processing the
     // file, otherwise the CompilerInstance will happily destroy them.
     CI.setFileManager(&AST->getFileManager());
     CI.setSourceManager(&AST->getSourceManager());
     CI.setPreprocessor(&AST->getPreprocessor());
     CI.setASTContext(&AST->getASTContext());

     // Initialize the action.
     if (!BeginSourceFileAction(CI, Filename))
       goto failure;

     /// Create the AST consumer.
     CI.setASTConsumer(CreateWrappedASTConsumer(CI, Filename));
     if (!CI.hasASTConsumer())
       goto failure;

     return true;
   }

   // Set up the file and source managers, if needed.
   if (!CI.hasFileManager())
     CI.createFileManager();
   if (!CI.hasSourceManager())
     CI.createSourceManager(CI.getFileManager());

   // IR files bypass the rest of initialization.
   if (InputKind == IK_LLVM_IR) {
     assert(hasIRSupport() &&
            "This action does not have IR file support!");

     // Inform the diagnostic client we are processing a source file.
     CI.getDiagnosticClient().BeginSourceFile(CI.getLangOpts(), 0);

     // Initialize the action.
     if (!BeginSourceFileAction(CI, Filename))
       goto failure;

     return true;
   }

   // Set up the preprocessor.
   CI.createPreprocessor();

   // Inform the diagnostic client we are processing a source file.
   CI.getDiagnosticClient().BeginSourceFile(CI.getLangOpts(),
                                            &CI.getPreprocessor());

   // Initialize the action.
   if (!BeginSourceFileAction(CI, Filename))
     goto failure;

   /// Create the AST context and consumer unless this is a preprocessor only
   /// action.
   if (!usesPreprocessorOnly()) {
     CI.createASTContext();

     llvm::OwningPtr<ASTConsumer> Consumer(
         CreateWrappedASTConsumer(CI, Filename));
     if (!Consumer)
       goto failure;

     CI.getASTContext().setASTMutationListener(Consumer->GetASTMutationListener());

     if (!CI.getPreprocessorOpts().ChainedIncludes.empty()) {
       // Convert headers to PCH and chain them.
       llvm::OwningPtr<ExternalASTSource> source;
       source.reset(ChainedIncludesSource::create(CI));
       if (!source)
         goto failure;
       CI.getASTContext().setExternalSource(source);

     } else if (!CI.getPreprocessorOpts().ImplicitPCHInclude.empty()) {
       // Use PCH.
       assert(hasPCHSupport() && "This action does not have PCH support!");
       ASTDeserializationListener *DeserialListener =
           Consumer->GetASTDeserializationListener();
       if (CI.getPreprocessorOpts().DumpDeserializedPCHDecls)
         DeserialListener = new DeserializedDeclsDumper(DeserialListener);
       if (!CI.getPreprocessorOpts().DeserializedPCHDeclsToErrorOn.empty())
         DeserialListener = new DeserializedDeclsChecker(CI.getASTContext(),
                          CI.getPreprocessorOpts().DeserializedPCHDeclsToErrorOn,
                                                         DeserialListener);
       CI.createPCHExternalASTSource(
                                 CI.getPreprocessorOpts().ImplicitPCHInclude,
                                 CI.getPreprocessorOpts().DisablePCHValidation,
                                 CI.getPreprocessorOpts().DisableStatCache,
                                 DeserialListener);
       if (!CI.getASTContext().getExternalSource())
         goto failure;
     }

     CI.setASTConsumer(Consumer.take());
     if (!CI.hasASTConsumer())
       goto failure;
   }

   // Initialize built-in info as long as we aren't using an external AST
   // source.
   if (!CI.hasASTContext() || !CI.getASTContext().getExternalSource()) {
     Preprocessor &PP = CI.getPreprocessor();
     PP.getBuiltinInfo().InitializeBuiltins(PP.getIdentifierTable(),
                                            PP.getLangOptions());
   }

   return true;

   // If we failed, reset state since the client will not end up calling the
   // matching EndSourceFile().
   failure:
   if (isCurrentFileAST()) {
     CI.setASTContext(0);
     CI.setPreprocessor(0);
     CI.setSourceManager(0);
     CI.setFileManager(0);
   }

   CI.getDiagnosticClient().EndSourceFile();
   setCurrentFile("", IK_None);
   setCompilerInstance(0);
   return false;
 }

 void FrontendAction::Execute() {
   CompilerInstance &CI = getCompilerInstance();

   // Initialize the main file entry. This needs to be delayed until after PCH
   // has loaded.
   if (isCurrentFileAST()) {
     // Set the main file ID to an empty file.
     //
     // FIXME: We probably shouldn't need this, but for now this is the
     // simplest way to reuse the logic in ParseAST.
     const char *EmptyStr = "";
     llvm::MemoryBuffer *SB =
       llvm::MemoryBuffer::getMemBuffer(EmptyStr, "<dummy input>");
     CI.getSourceManager().createMainFileIDForMemBuffer(SB);
   } else {
     if (!CI.InitializeSourceManager(getCurrentFile()))
       return;
   }

   if (CI.hasFrontendTimer()) {
     llvm::TimeRegion Timer(CI.getFrontendTimer());
     ExecuteAction();
   }
   else ExecuteAction();
 }

 void FrontendAction::EndSourceFile() {
   CompilerInstance &CI = getCompilerInstance();

   // Inform the diagnostic client we are done with this source file.
   CI.getDiagnosticClient().EndSourceFile();

   // Finalize the action.
   EndSourceFileAction();

   // Release the consumer and the AST, in that order since the consumer may
   // perform actions in its destructor which require the context.
   //
   // FIXME: There is more per-file stuff we could just drop here?
   if (CI.getFrontendOpts().DisableFree) {
     CI.takeASTConsumer();
     if (!isCurrentFileAST()) {
       CI.takeSema();
       CI.resetAndLeakASTContext();
     }
   } else {
     if (!isCurrentFileAST()) {
       CI.setSema(0);
       CI.setASTContext(0);
     }
     CI.setASTConsumer(0);
   }

   // Inform the preprocessor we are done.
   if (CI.hasPreprocessor())
     CI.getPreprocessor().EndSourceFile();

   if (CI.getFrontendOpts().ShowStats) {
     llvm::errs() << "\nSTATISTICS FOR '" << getCurrentFile() << "':\n";
     CI.getPreprocessor().PrintStats();
     CI.getPreprocessor().getIdentifierTable().PrintStats();
     CI.getPreprocessor().getHeaderSearchInfo().PrintStats();
     CI.getSourceManager().PrintStats();
     llvm::errs() << "\n";
   }

   // Cleanup the output streams, and erase the output files if we encountered
   // an error.
   CI.clearOutputFiles(/*EraseFiles=*/CI.getDiagnostics().hasErrorOccurred());

   if (isCurrentFileAST()) {
     CI.takeSema();
     CI.resetAndLeakASTContext();
     CI.resetAndLeakPreprocessor();
     CI.resetAndLeakSourceManager();
     CI.resetAndLeakFileManager();
   }

   setCompilerInstance(0);
   setCurrentFile("", IK_None);
 }

 //===----------------------------------------------------------------------===//
 // Utility Actions
 //===----------------------------------------------------------------------===//

 void ASTFrontendAction::ExecuteAction() {
   CompilerInstance &CI = getCompilerInstance();

   // FIXME: Move the truncation aspect of this into Sema, we delayed this till
   // here so the source manager would be initialized.
   if (hasCodeCompletionSupport() &&
       !CI.getFrontendOpts().CodeCompletionAt.FileName.empty())
     CI.createCodeCompletionConsumer();

   // Use a code completion consumer?
   CodeCompleteConsumer *CompletionConsumer = 0;
   if (CI.hasCodeCompletionConsumer())
     CompletionConsumer = &CI.getCodeCompletionConsumer();

   if (!CI.hasSema())
     CI.createSema(getTranslationUnitKind(), CompletionConsumer);

   ParseAST(CI.getSema(), CI.getFrontendOpts().ShowStats);
 }

 ASTConsumer *
 PreprocessorFrontendAction::CreateASTConsumer(CompilerInstance &CI,
                                               StringRef InFile) {
   llvm_unreachable("Invalid CreateASTConsumer on preprocessor action!");
 }

 ASTConsumer *WrapperFrontendAction::CreateASTConsumer(CompilerInstance &CI,
                                                       StringRef InFile) {
   return WrappedAction->CreateASTConsumer(CI, InFile);
 }
 bool WrapperFrontendAction::BeginInvocation(CompilerInstance &CI) {
   return WrappedAction->BeginInvocation(CI);
 }
 bool WrapperFrontendAction::BeginSourceFileAction(CompilerInstance &CI,
                                                   StringRef Filename) {
   WrappedAction->setCurrentFile(getCurrentFile(), getCurrentFileKind());
   WrappedAction->setCompilerInstance(&CI);
   return WrappedAction->BeginSourceFileAction(CI, Filename);
 }
 void WrapperFrontendAction::ExecuteAction() {
   WrappedAction->ExecuteAction();
 }
 void WrapperFrontendAction::EndSourceFileAction() {
   WrappedAction->EndSourceFileAction();
 }

 bool WrapperFrontendAction::usesPreprocessorOnly() const {
   return WrappedAction->usesPreprocessorOnly();
 }
 TranslationUnitKind WrapperFrontendAction::getTranslationUnitKind() {
   return WrappedAction->getTranslationUnitKind();
 }
 bool WrapperFrontendAction::hasPCHSupport() const {
   return WrappedAction->hasPCHSupport();
 }
 bool WrapperFrontendAction::hasASTFileSupport() const {
   return WrappedAction->hasASTFileSupport();
 }
 bool WrapperFrontendAction::hasIRSupport() const {
   return WrappedAction->hasIRSupport();
 }
 bool WrapperFrontendAction::hasCodeCompletionSupport() const {
   return WrappedAction->hasCodeCompletionSupport();
 }

 WrapperFrontendAction::WrapperFrontendAction(FrontendAction *WrappedAction)
   : WrappedAction(WrappedAction) {}
	//===--- FrontendAction.cpp -----------------------------------------------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//

	#include "clang/Frontend/FrontendAction.h"
	#include "clang/AST/ASTConsumer.h"
	#include "clang/AST/ASTContext.h"
	#include "clang/AST/DeclGroup.h"
	#include "clang/Lex/HeaderSearch.h"
	#include "clang/Lex/Preprocessor.h"
	#include "clang/Frontend/ASTUnit.h"
	#include "clang/Frontend/ChainedIncludesSource.h"
	#include "clang/Frontend/CompilerInstance.h"
	#include "clang/Frontend/FrontendDiagnostic.h"
	#include "clang/Frontend/FrontendPluginRegistry.h"
	#include "clang/Frontend/MultiplexConsumer.h"
	#include "clang/Parse/ParseAST.h"
	#include "clang/Serialization/ASTDeserializationListener.h"
	#include "clang/Serialization/ASTReader.h"
	#include "llvm/Support/MemoryBuffer.h"
	#include "llvm/Support/Timer.h"
	#include "llvm/Support/ErrorHandling.h"
	#include "llvm/Support/raw_ostream.h"
	using namespace clang;

	namespace {

	class DelegatingDeserializationListener : public ASTDeserializationListener {
	ASTDeserializationListener *Previous;

	public:
	explicit DelegatingDeserializationListener(
	ASTDeserializationListener *Previous)
	: Previous(Previous) { }

	virtual void ReaderInitialized(ASTReader *Reader) {
	if (Previous)
	Previous->ReaderInitialized(Reader);
	}
	virtual void IdentifierRead(serialization::IdentID ID,
	IdentifierInfo *II) {
	if (Previous)
	Previous->IdentifierRead(ID, II);
	}
	virtual void TypeRead(serialization::TypeIdx Idx, QualType T) {
	if (Previous)
	Previous->TypeRead(Idx, T);
	}
	virtual void DeclRead(serialization::DeclID ID, const Decl *D) {
	if (Previous)
	Previous->DeclRead(ID, D);
	}
	virtual void SelectorRead(serialization::SelectorID ID, Selector Sel) {
	if (Previous)
	Previous->SelectorRead(ID, Sel);
	}
	virtual void MacroDefinitionRead(serialization::PreprocessedEntityID PPID,
	MacroDefinition *MD) {
	if (Previous)
	Previous->MacroDefinitionRead(PPID, MD);
	}
	};

	/// \brief Dumps deserialized declarations.
	class DeserializedDeclsDumper : public DelegatingDeserializationListener {
	public:
	explicit DeserializedDeclsDumper(ASTDeserializationListener *Previous)
	: DelegatingDeserializationListener(Previous) { }

	virtual void DeclRead(serialization::DeclID ID, const Decl *D) {
	llvm::outs() << "PCH DECL: " << D->getDeclKindName();
	if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
	llvm::outs() << " - " << ND->getNameAsString();
	llvm::outs() << "\n";

	DelegatingDeserializationListener::DeclRead(ID, D);
	}
	};

	/// \brief Checks deserialized declarations and emits error if a name
	/// matches one given in command-line using -error-on-deserialized-decl.
	class DeserializedDeclsChecker : public DelegatingDeserializationListener {
	ASTContext &Ctx;
	std::set<std::string> NamesToCheck;

	public:
	DeserializedDeclsChecker(ASTContext &Ctx,
	const std::set<std::string> &NamesToCheck,
	ASTDeserializationListener *Previous)
	: DelegatingDeserializationListener(Previous),
	Ctx(Ctx), NamesToCheck(NamesToCheck) { }

	virtual void DeclRead(serialization::DeclID ID, const Decl *D) {
	if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
	if (NamesToCheck.find(ND->getNameAsString()) != NamesToCheck.end()) {
	unsigned DiagID
	= Ctx.getDiagnostics().getCustomDiagID(DiagnosticsEngine::Error,
	"%0 was deserialized");
	Ctx.getDiagnostics().Report(Ctx.getFullLoc(D->getLocation()), DiagID)
	<< ND->getNameAsString();
	}

	DelegatingDeserializationListener::DeclRead(ID, D);
	}
	};

	} // end anonymous namespace

	FrontendAction::FrontendAction() : Instance(0) {}

	FrontendAction::~FrontendAction() {}

	void FrontendAction::setCurrentFile(StringRef Value, InputKind Kind,
	ASTUnit *AST) {
	CurrentFile = Value;
	CurrentFileKind = Kind;
	CurrentASTUnit.reset(AST);
	}

	ASTConsumer* FrontendAction::CreateWrappedASTConsumer(CompilerInstance &CI,
	StringRef InFile) {
	ASTConsumer* Consumer = CreateASTConsumer(CI, InFile);
	if (!Consumer)
	return 0;

	if (CI.getFrontendOpts().AddPluginActions.size() == 0)
	return Consumer;

	// Make sure the non-plugin consumer is first, so that plugins can't
	// modifiy the AST.
	std::vector<ASTConsumer*> Consumers(1, Consumer);

	for (size_t i = 0, e = CI.getFrontendOpts().AddPluginActions.size();
	i != e; ++i) {
	// This is O(\|plugins\| * \|add_plugins\|), but since both numbers are
	// way below 50 in practice, that's ok.
	for (FrontendPluginRegistry::iterator
	it = FrontendPluginRegistry::begin(),
	ie = FrontendPluginRegistry::end();
	it != ie; ++it) {
	if (it->getName() == CI.getFrontendOpts().AddPluginActions[i]) {
	llvm::OwningPtr<PluginASTAction> P(it->instantiate());
	FrontendAction* c = P.get();
	if (P->ParseArgs(CI, CI.getFrontendOpts().AddPluginArgs[i]))
	Consumers.push_back(c->CreateASTConsumer(CI, InFile));
	}
	}
	}

	return new MultiplexConsumer(Consumers);
	}

	bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
	StringRef Filename,
	InputKind InputKind) {
	assert(!Instance && "Already processing a source file!");
	assert(!Filename.empty() && "Unexpected empty filename!");
	setCurrentFile(Filename, InputKind);
	setCompilerInstance(&CI);

	if (!BeginInvocation(CI))
	goto failure;

	// AST files follow a very different path, since they share objects via the
	// AST unit.
	if (InputKind == IK_AST) {
	assert(!usesPreprocessorOnly() &&
	"Attempt to pass AST file to preprocessor only action!");
	assert(hasASTFileSupport() &&
	"This action does not have AST file support!");

	llvm::IntrusiveRefCntPtr<DiagnosticsEngine> Diags(&CI.getDiagnostics());
	std::string Error;
	ASTUnit *AST = ASTUnit::LoadFromASTFile(Filename, Diags,
	CI.getFileSystemOpts());
	if (!AST)
	goto failure;

	setCurrentFile(Filename, InputKind, AST);

	// Set the shared objects, these are reset when we finish processing the
	// file, otherwise the CompilerInstance will happily destroy them.
	CI.setFileManager(&AST->getFileManager());
	CI.setSourceManager(&AST->getSourceManager());
	CI.setPreprocessor(&AST->getPreprocessor());
	CI.setASTContext(&AST->getASTContext());

	// Initialize the action.
	if (!BeginSourceFileAction(CI, Filename))
	goto failure;

	/// Create the AST consumer.
	CI.setASTConsumer(CreateWrappedASTConsumer(CI, Filename));
	if (!CI.hasASTConsumer())
	goto failure;

	return true;
	}

	// Set up the file and source managers, if needed.
	if (!CI.hasFileManager())
	CI.createFileManager();
	if (!CI.hasSourceManager())
	CI.createSourceManager(CI.getFileManager());

	// IR files bypass the rest of initialization.
	if (InputKind == IK_LLVM_IR) {
	assert(hasIRSupport() &&
	"This action does not have IR file support!");

	// Inform the diagnostic client we are processing a source file.
	CI.getDiagnosticClient().BeginSourceFile(CI.getLangOpts(), 0);

	// Initialize the action.
	if (!BeginSourceFileAction(CI, Filename))
	goto failure;

	return true;
	}

	// Set up the preprocessor.
	CI.createPreprocessor();

	// Inform the diagnostic client we are processing a source file.
	CI.getDiagnosticClient().BeginSourceFile(CI.getLangOpts(),
	&CI.getPreprocessor());

	// Initialize the action.
	if (!BeginSourceFileAction(CI, Filename))
	goto failure;

	/// Create the AST context and consumer unless this is a preprocessor only
	/// action.
	if (!usesPreprocessorOnly()) {
	CI.createASTContext();

	llvm::OwningPtr<ASTConsumer> Consumer(
	CreateWrappedASTConsumer(CI, Filename));
	if (!Consumer)
	goto failure;

	CI.getASTContext().setASTMutationListener(Consumer->GetASTMutationListener());

	if (!CI.getPreprocessorOpts().ChainedIncludes.empty()) {
	// Convert headers to PCH and chain them.
	llvm::OwningPtr<ExternalASTSource> source;
	source.reset(ChainedIncludesSource::create(CI));
	if (!source)
	goto failure;
	CI.getASTContext().setExternalSource(source);

	} else if (!CI.getPreprocessorOpts().ImplicitPCHInclude.empty()) {
	// Use PCH.
	assert(hasPCHSupport() && "This action does not have PCH support!");
	ASTDeserializationListener *DeserialListener =
	Consumer->GetASTDeserializationListener();
	if (CI.getPreprocessorOpts().DumpDeserializedPCHDecls)
	DeserialListener = new DeserializedDeclsDumper(DeserialListener);
	if (!CI.getPreprocessorOpts().DeserializedPCHDeclsToErrorOn.empty())
	DeserialListener = new DeserializedDeclsChecker(CI.getASTContext(),
	CI.getPreprocessorOpts().DeserializedPCHDeclsToErrorOn,
	DeserialListener);
	CI.createPCHExternalASTSource(
	CI.getPreprocessorOpts().ImplicitPCHInclude,
	CI.getPreprocessorOpts().DisablePCHValidation,
	CI.getPreprocessorOpts().DisableStatCache,
	DeserialListener);
	if (!CI.getASTContext().getExternalSource())
	goto failure;
	}

	CI.setASTConsumer(Consumer.take());
	if (!CI.hasASTConsumer())
	goto failure;
	}

	// Initialize built-in info as long as we aren't using an external AST
	// source.
	if (!CI.hasASTContext() \|\| !CI.getASTContext().getExternalSource()) {
	Preprocessor &PP = CI.getPreprocessor();
	PP.getBuiltinInfo().InitializeBuiltins(PP.getIdentifierTable(),
	PP.getLangOptions());
	}

	return true;

	// If we failed, reset state since the client will not end up calling the
	// matching EndSourceFile().
	failure:
	if (isCurrentFileAST()) {
	CI.setASTContext(0);
	CI.setPreprocessor(0);
	CI.setSourceManager(0);
	CI.setFileManager(0);
	}

	CI.getDiagnosticClient().EndSourceFile();
	setCurrentFile("", IK_None);
	setCompilerInstance(0);
	return false;
	}

	void FrontendAction::Execute() {
	CompilerInstance &CI = getCompilerInstance();

	// Initialize the main file entry. This needs to be delayed until after PCH
	// has loaded.
	if (isCurrentFileAST()) {
	// Set the main file ID to an empty file.
	//
	// FIXME: We probably shouldn't need this, but for now this is the
	// simplest way to reuse the logic in ParseAST.
	const char *EmptyStr = "";
	llvm::MemoryBuffer *SB =
	llvm::MemoryBuffer::getMemBuffer(EmptyStr, "<dummy input>");
	CI.getSourceManager().createMainFileIDForMemBuffer(SB);
	} else {
	if (!CI.InitializeSourceManager(getCurrentFile()))
	return;
	}

	if (CI.hasFrontendTimer()) {
	llvm::TimeRegion Timer(CI.getFrontendTimer());
	ExecuteAction();
	}
	else ExecuteAction();
	}

	void FrontendAction::EndSourceFile() {
	CompilerInstance &CI = getCompilerInstance();

	// Inform the diagnostic client we are done with this source file.
	CI.getDiagnosticClient().EndSourceFile();

	// Finalize the action.
	EndSourceFileAction();

	// Release the consumer and the AST, in that order since the consumer may
	// perform actions in its destructor which require the context.
	//
	// FIXME: There is more per-file stuff we could just drop here?
	if (CI.getFrontendOpts().DisableFree) {
	CI.takeASTConsumer();
	if (!isCurrentFileAST()) {
	CI.takeSema();
	CI.resetAndLeakASTContext();
	}
	} else {
	if (!isCurrentFileAST()) {
	CI.setSema(0);
	CI.setASTContext(0);
	}
	CI.setASTConsumer(0);
	}

	// Inform the preprocessor we are done.
	if (CI.hasPreprocessor())
	CI.getPreprocessor().EndSourceFile();

	if (CI.getFrontendOpts().ShowStats) {
	llvm::errs() << "\nSTATISTICS FOR '" << getCurrentFile() << "':\n";
	CI.getPreprocessor().PrintStats();
	CI.getPreprocessor().getIdentifierTable().PrintStats();
	CI.getPreprocessor().getHeaderSearchInfo().PrintStats();
	CI.getSourceManager().PrintStats();
	llvm::errs() << "\n";
	}

	// Cleanup the output streams, and erase the output files if we encountered
	// an error.
	CI.clearOutputFiles(/EraseFiles=/CI.getDiagnostics().hasErrorOccurred());

	if (isCurrentFileAST()) {
	CI.takeSema();
	CI.resetAndLeakASTContext();
	CI.resetAndLeakPreprocessor();
	CI.resetAndLeakSourceManager();
	CI.resetAndLeakFileManager();
	}

	setCompilerInstance(0);
	setCurrentFile("", IK_None);
	}

	//===----------------------------------------------------------------------===//
	// Utility Actions
	//===----------------------------------------------------------------------===//

	void ASTFrontendAction::ExecuteAction() {
	CompilerInstance &CI = getCompilerInstance();

	// FIXME: Move the truncation aspect of this into Sema, we delayed this till
	// here so the source manager would be initialized.
	if (hasCodeCompletionSupport() &&
	!CI.getFrontendOpts().CodeCompletionAt.FileName.empty())
	CI.createCodeCompletionConsumer();

	// Use a code completion consumer?
	CodeCompleteConsumer *CompletionConsumer = 0;
	if (CI.hasCodeCompletionConsumer())
	CompletionConsumer = &CI.getCodeCompletionConsumer();

	if (!CI.hasSema())
	CI.createSema(getTranslationUnitKind(), CompletionConsumer);

	ParseAST(CI.getSema(), CI.getFrontendOpts().ShowStats);
	}

	ASTConsumer *
	PreprocessorFrontendAction::CreateASTConsumer(CompilerInstance &CI,
	StringRef InFile) {
	llvm_unreachable("Invalid CreateASTConsumer on preprocessor action!");
	}

	ASTConsumer *WrapperFrontendAction::CreateASTConsumer(CompilerInstance &CI,
	StringRef InFile) {
	return WrappedAction->CreateASTConsumer(CI, InFile);
	}
	bool WrapperFrontendAction::BeginInvocation(CompilerInstance &CI) {
	return WrappedAction->BeginInvocation(CI);
	}
	bool WrapperFrontendAction::BeginSourceFileAction(CompilerInstance &CI,
	StringRef Filename) {
	WrappedAction->setCurrentFile(getCurrentFile(), getCurrentFileKind());
	WrappedAction->setCompilerInstance(&CI);
	return WrappedAction->BeginSourceFileAction(CI, Filename);
	}
	void WrapperFrontendAction::ExecuteAction() {
	WrappedAction->ExecuteAction();
	}
	void WrapperFrontendAction::EndSourceFileAction() {
	WrappedAction->EndSourceFileAction();
	}

	bool WrapperFrontendAction::usesPreprocessorOnly() const {
	return WrappedAction->usesPreprocessorOnly();
	}
	TranslationUnitKind WrapperFrontendAction::getTranslationUnitKind() {
	return WrappedAction->getTranslationUnitKind();
	}
	bool WrapperFrontendAction::hasPCHSupport() const {
	return WrappedAction->hasPCHSupport();
	}
	bool WrapperFrontendAction::hasASTFileSupport() const {
	return WrappedAction->hasASTFileSupport();
	}
	bool WrapperFrontendAction::hasIRSupport() const {
	return WrappedAction->hasIRSupport();
	}
	bool WrapperFrontendAction::hasCodeCompletionSupport() const {
	return WrappedAction->hasCodeCompletionSupport();
	}

	WrapperFrontendAction::WrapperFrontendAction(FrontendAction *WrappedAction)
	: WrappedAction(WrappedAction) {}